Study on Reliability Improvement of Main Steam Isolation Valve Control in Nuclear Power Plants

Abstract

There is a safety hazard in the interlock control logic of the second circuit main steam isolation valves of the CPR1000 nuclear power unit. During reactor power operation, any abnormal full-close limit switch signal of valves may lead to a reactor shutdown event or even a Safety Injection of nuclear reactor. In this Paper, the control strategy of the second circuit main steam isolation valves is analyzed and demonstrated, and after Probabilistic Safety Assessment(PSA), a feasible improvement plan is proposed, which effectively improves the control reliability of the second circuit system in nuclear power plants.